Earth, Moon, and Planets

, Volume 67, Issue 1–3, pp 51–65

Giant planet formation

A comparative view of gas-accretion
  • G. Wuchterl
Article

Abstract

The accumulation of giant planets involves processes typical for terrestrial planet formation as well as gasdynamic processes that were previously known only in stars. The condensible element cores of the gas-giants grow by solid body accretion while envelope formation is governed by ‘stellar-like’ equilibria and the dynamic departures thereof. Two hypotheses for forming Uranus/Neptune-type planets — at sufficiently large heliocentric distances while allowing accretion of massive gaseous envelopes, i.e. Jupiter-type planets at intermediate distances — have been worked out in detailed numerical calculations: (1) Hydrostatic gas-accretion models with time-dependent solid body accretion-rates show a slow-down of core-accretion at the appropriate masses of Uranus and Neptune. As a consequence, gas-accretion also stagnates and a window is opened for removing the solar nebula during a time of roughly constant envelope mass. (2) Gasdynamic calculations of envelope accretion for constant planetesimal accretion-rates show a dynamic transition to new envelope equilibria at the so called critical mass. For a wide range of solar nebula conditions the new envelopes have respective masses similar to those of Uranus and Neptune and are more tightly bound to the cores. The transitions occur under lower density conditions typical for the outer parts of the solar nebula, whereas for higher densities, i.e. closer to the Sun, gasdynamic envelope accretion sets in and is able to proceed to Jupiter-masses.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Bodenheimer, P. and Pollack, J.B. (1986) Calculations of the accretion and evolution of the giant planets: The effect of solid cores,Icarus 67, 391–408.Google Scholar
  2. Boss, A.P., Morfill, G.E., and Tscharnuter, W.M. (1989) Models of the Formation and Evolution of the Solar Nebula, in S.K. Atreya, J.B. Pollack and M.S. Matthews, (eds.),Origin and Evolution of Planetary and Satellite Atmospheres, Univ. of Arizona Press, Tucson, pp. 35–77.Google Scholar
  3. Chabrier, G., Saumon, D., Hubbard, W.D., and Lunine, J.I. (1992) The Molecular-Metallic Transition of Hydrogen and the Structure of Jupiter and Saturn,Astrophys. Journ. 319, 817–826.Google Scholar
  4. Greenzweig, Y. and Lissauer, J.J. (1990) Accretion Rates of Protoplanets II. Gaussian Distribution of Planetesimal Velocities,Icarus 100, 440–463.Google Scholar
  5. Götz, M. (1993)Die Entwicklung yon Proto-Gasplaneten mit Drehimpuls — Strahlungshydrodynamische Rechnungen, Dissertation, Univ. Heidelberg.Google Scholar
  6. Hubbard, W.B. and Marley, M.S. (1989) Optimized Jupiter, Saturn and Uranus Interior Models,Icarus 78, 102–118.Google Scholar
  7. Hubbard, W.B., Nellis, W.J., Mitchell, A.C., Holmes, N.C., Limaye, S.S., and McCandless, P.C. (1991) Interior Structure of Neptune: Comparison with Uranus,Science 253, 648–651.Google Scholar
  8. Kippenhahn, R. and Weigert, A. (1990)Stellar Structure and Evolution, Springer-Verlag, Berlin.Google Scholar
  9. Korycansky, D.G., Bodenheimer, P., and Pollack, J.B. (1991) Numerical models of giant planet formation with rotation,Icarus 92, 234–251.Google Scholar
  10. Kusaka, T., Nakano, T. and Hayashi, C. (1970) Growth of Solid Particles in the Primordial Solar Nebula,Prog. Theor. Phys. 44, 1580–1595.Google Scholar
  11. Lissauer, J.J., Pollack, J.B., Wetherill, G.W. and Stevenson, D.J., (1995) Formation of the Neptune System, inNeptune Univ. Arizona Press, in prep.Google Scholar
  12. Mizuno, H. (1980) Formation of the Giant Planets,Prog. Theor. Phys. 64, 544–557.Google Scholar
  13. Perri, F. and Cameron, A.G.W. (1974) Hydrodynamic instability of the solar nebula in the presence of a planetary core,Icarus 22, 416–425.Google Scholar
  14. Pollack, J.B. (1985) Formation of the giant planets and their satellite-ring systems: An overview, in D.C. Black and M.S. Matthews (eds.)Protostars and Planets II, Univ. Arizona Press, Tucson.Google Scholar
  15. Stevenson, D.J. (1982) Formation of the giant planets,Planet. Space Sci. 30, 755–764.Google Scholar
  16. Stevenson, D.J. (1984) On forming giant planets quickly (superganymedean puffballs!),Lunar Planet. Sci. XV, 821–822 (abstract).Google Scholar
  17. Tajima, N. (1994)Giant Planet Formation: Dynamical Stability of the Envelope, Master Thesis, Univ. Tokyo.Google Scholar
  18. Wuchterl, G. (1990) Hydrodynamics of Giant Planet Formation I: Overviewing theκ-MechanismAstron. Astrophys.,238:83–94.Google Scholar
  19. Wuchterl, G. (1991a) Hydrodynamics of Giant Planet Formation II: Model Equations and Critical MassIcarus 91, 39–52.Google Scholar
  20. Wuchterl, G. (1991b) Hydrodynamics of Giant Planet Formation III: Jupiter's Nucleated Instability” ’.Icarus 91, 53–64.Google Scholar
  21. Wuchterl, G., 1993 The Critical Mass for Protoplanets Revisited: Massive Envelopes Through Convection” ’.Icarus 106, 323–334.Google Scholar
  22. Zharkov, V.N. and Gudkova, T.V. (1991)Ann. Geophys. 9, 357.Google Scholar
  23. Zharkov, V.N. and Gudkova, T.V. (1992) Modern Models of Giant Planets, in Y. Soyono and M.H. Manghnani (eds.),High Pressure Research: Application to Earth and Planetary Sciences, Terra Sci. Publ. Co. (TERRAPUB), Tokyo / American Geophysical Union, Washington, D.C..Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • G. Wuchterl
    • 1
  1. 1.Institut für Astronomie der Universität WienWienAustria

Personalised recommendations